Hybrid Powertrain Creep Torque Control for Rollback Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid powertrain systems face challenges in efficiently managing axle torque during low-speed operations, particularly when the vehicle is stationary or moving uphill, as existing systems struggle to minimize energy loss and prevent vehicle rollback without excessive operator braking force.
Innovation Solution
The implementation of an axle creep torque control routine that determines an initial creep torque command based on vehicle speed and direction, adjusts it in response to operator braking requests, and operates the hybrid powertrain to generate axle torque, thereby minimizing energy loss and preventing rollback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the hybrid powertrain generates creep torque to prevent vehicle rollback on inclines, then vehicle stability is improved, but energy loss increases
Solution Approach 1:
The system dynamically adjusts the creep torque command based on real-time detection of operator braking requests and changes in vehicle speed direction. The controller modifies the initial creep torque command to account for operator braking inputs, thereby optimizing the balance between maintaining vehicle stability and minimizing energy loss during low-speed operations on inclines.
Solution Approach 2:
The system implements feedback by continuously monitoring operator braking requests and changes in vehicle speed direction relative to the operator-selected direction of travel. This feedback mechanism allows the controller to adjust the creep torque command in real-time, ensuring that torque generation is optimized based on actual operating conditions, thereby reducing unnecessary energy loss while maintaining stability.
2Loss of energy
If the system adjusts creep torque to minimize energy loss, then energy efficiency is improved, but the need for operator braking force reduction may be compromised
Solution Approach 1:
The system performs preliminary action by detecting operator braking requests and changes in vehicle speed direction before they significantly impact vehicle operation. By proactively adjusting the creep torque command in response to these detected changes, the system reduces the need for operator braking force while simultaneously minimizing energy loss, as the torque adjustment is made in advance based on detected operational trends.
3Ease of operation
If the hybrid powertrain operates at low speeds to maintain vehicle position, then vehicle control is improved, but energy efficiency deteriorates
Solution Approach 1:
The system applies partial action by generating only the necessary creep torque required to maintain vehicle position and prevent rollback, rather than operating at full power. The controller adjusts the torque command proportionally based on detected operator braking requests and vehicle speed direction changes, thereby maintaining adequate vehicle control while minimizing energy consumption during low-speed operations.
Data Source
AI summary
A method for operating a powertrain system of a vehicle includes determining an initial creep torque command in an operator-selected direction of travel, adjusting the initial creep torque command responsive to an operator braking request and responsive to a change in direction of vehicle speed relative to the operator-selected direction of travel, and operating the hybrid powertrain to generate axle torque in response to the adjusted creep torque command.